Heathkit H-8 Part 1: Trying out the Tape Board, and Designing a Speech Synthesizer
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- Опубліковано 20 гру 2022
- In this video I receive a Heathkit H-8. I wanted one of these since seeing them in the Heathkit catalogs back in the early 80s. This video series is going to start out with a fairly plain H8 computer and slowly build it up into a fully provisioned H8. I'll be using both boards found on the Internet (most notably by Norberto and Les of SEBHC) as well as a few of my own boards. In this video, I try to get the tape board working, and eventually bypass the tape circuitry and inject the tape data stream directly into the tape controller's 8251. After a successful load and a short "Benton Harbor Basic" demo, I then design a speech synthesizer card, build it, and try it out. For more vintage computer projects, see www.smbaker.com/
- Наука та технологія
I have an H-8 we bought back in 1978 and I used through college. We had 56k-RAM as 4k and 16 k boards, the quad serial port card, the tape/serial card, the H17 disk and the CPU card.
We upgraded it to the Z80-CPU card and did mods for 3mHz and then 4mHz. I threw out the tape/serial card and the RAM cars as the RAM chips were all dying. I designed a 64k DRAM card back in '82 IIRC. Also designed a TMS9918 graphic display card. Moved the guts to a 19" rack case I had. I now regret throwing out the floppies. Heck, by '85 they were impossible to get.
Initially, I remember loading mbasic, then adventure or space war off tape and having it fail. Added the H17 disk drives and started with HDOS. The Z80 upgrade allowed running CP/M.
Started with a H-12 terminal then upgraded later to the H-19.
Looking forward to what you do with this.
I built one and all the peripherals for my job at a custom photo lab in the late 70's and we had someone write a basic program to track orders which was not automatic but needed entry for each department. Later we sold all the Heathkit gear to a guy who collected Heathkit computers with the plan to open a museum. IIRC Bruce Gerwertz was his name. TRS80's were our next step in tracking, invoicing, and billing.
Glad you are working with the H8, that was my first system back in 70's and it was a well designed box mostly, for its time. I still have several H8's and use them once in a while with CPM and actually do real work with them. Not the speed demons we have now but a great way to learn assembly language and understand the fundamentals of computer theory.
very nice
I remember the key sequence to boot up. Maybe hundreds and boards passed through my hands after hiring in factory assembly test 1978.
I suggest "Split Octal".
Nice work! 🎉 Keep the parts coming! Thank you 😊
It was '76. I worked for Heathkit. The H-8 in Red is missing from the tag. Benton Harbor Basic was later called: *HDOS* on H-89!
I also fought to have it program in HEX, but was turned down! errr WHO DOES OCTAL!
H-8 computer display in offset octal. I worked at Zenith Data system in the 1980's.
@@stevenretroworkshop2113 - Zenith was a dirty word for us. They bought Heathkit, then shut us down! Sorry.
I built an H8 and the H9 CRT. I never knew that the 3rd party add on boards existed. (That was about 47 years ago)
Hey! You got one! Nice!!! I have one on the way, supposedly, but I think it may have been an ebay scam, lol.
Tape system was problematic. I got the floppy disk for my H8 and that worked wonderfully. The tin plated connectors were crap... Quite often removing then reinserting the boards to keeping things working. Looking forward to your H8 vids. Thanks.
What about creating a board that can decode FSK and turn that into data and also output FSK so you can save it on tape and use 1275/1445Hz which might allow for more reliable loading and saving of programs, you might have a look at the Mainline ST5 Terminal circuit you might be able to use in your computer.